If you want to ensure you have adequate passwords but don't have the time or interest to study the topic, there's a useful basic article on how to devise strong passwords over at the NY Times. It summarizes key points in 9 simple rules of thumb. Also see the follow-up article for useful reader feedback. Stay safe!

* how you decide your salt (ie is it the full website address inc protocol handler, the URI or just the website name?

If they can analyze raw passphrases for behavioural patterns in chosen words, they can surely do the same for the salt. As you say before, they don't have to break everyone's - just the easy ones.

* how the salt is encoded into the passphrase (eg is the salt and passphrase concatenated, and if so in which order? or is the passphrase hashed then the hash salted? etc)

They can just use the service to generate the hash, so they don't even need to figure it out. They'll probably be able to automate the whole process and just target the, say, top 20 most used generators.

So no, in all practicality you cannot reverse engineer in the method you describe and using "raw" passphrases like you keep advocating is still quite a bit less secure in comparison.

They wouldn't need to reverse engineer. They could figure out the most popular generators and get those generators do the work of generating. All they will have to do is to get all the output variants and try it. They could even just use the web service you linked to, feed in its guesses, then scrape the returned webpage for the generated hashes.

Seriously mate, I urge you to read up on this stuff as there's clearly some large gaps in your understanding here; which would be fine if you were asking questions, but instead you're trying to argue facts based on these gaps of knowledge and -with the greatest of respect- it's getting quite frustrating having to debunk all these misconceptions which you'd easily be able to debunk yourself if bothered to do a little independent research